1. Field of the Invention
The present invention relates to a both-side recording apparatus in which both-side recording can be performed to a recording medium inverted by a sheet inversion unit, particularly to the both-side recording apparatus with a sheet transport mechanism having a pair of sheet transport rollers including a sheet transport roller and a pinch roller and a pair of sheet discharge roller arranged on the downstream side of the pair of sheet transport rollers in a transport direction.
2. Related Background Art
In an inkjet recording apparatus which can perform the both-side recording, some methods have been realized or proposed. In these methods, after the recording of the surface (front surface) of the recording paper is terminated, the transport direction of the recording paper is inverted, the recording paper is fed into an inversion device, the recording paper is transported again by the same sheet transport unit after termination of inversion operation, and the recording is performed to a reverse surface of the recording paper by the same recording unit.
In the invention disclosed in U.S. Pat. No. 6,332,068, the recording paper is supported by the sheet transport rollers while sandwiched by the sheet transport rollers when recording operation of the front surface of the recording paper is terminated, and a rotating direction of the sheet transport roller is directly reversed to transport the recording paper to the inversion unit. In the invention disclosed in Japanese Patent Application Laid-Open No. 2002-067407, after the recording operation of the front surface of the recording paper is performed while the recording paper is transported to the downstream side where the recording paper has already disengaged from the sheet transport roller, the transport direction of the recording paper is reversed, and the sheet transport rollers support the recording paper while sandwiching the recording paper again by utilizing a guide member. In both the methods, a region where the recording of the front surface is terminated and ink is fixed is supported by the sheet transport roller while sandwiched by the sheet transport roller again, and the recording paper is transported.
However, there are some restrictions in the above conventional examples. In the invention disclosed in U.S. Pat. No. 6,332,068, because a paper supporting and sandwiching space for the sheet transport rollers is required, it is impossible that an array of discharge ports of a recording head is arranged to proximity of a nip position. Therefore, a blank space where the recording operation cannot be performed is not prevented from remaining in a rear end portion of the recording paper. In the invention disclosed in Japanese Patent Application Laid-Open No. 2002-067407, the blank space in a rear end portion of the recording paper can be eliminated. However, in the case where the recording operation is performed by the inkjet recording, since deformation such as surface waviness influenced by swelling of the recording paper occurs, there is a possibility that paper jam is generated when the sheet transport rollers support the recording paper while sandwiching the recording paper. Further, since the sheet transport rollers support the region where the recording the ink is fixed while sandwiching the region again to transport, it is necessary to wait until the ink is completely dried to be fixed. In consideration of various kinds of conditions, it is necessary to secure sufficient dry standby time in order not to transfer the ink to the roller side in any case.